WAL and postmaster status checks
remove unnecessary disable/enable _wal functions (denish confirms the configuration can always retain the options regardless of whether it is running in primary or replicant modes
prompt to continue on failure creating trigger file, instead of forcing exit
omnitpitr-backup-master call when promoting a new host
allow commands to be run which are expected to fail (in which case return values are essentially reversed); added separate postmaster status checks (one to see if it's online, one to see if it's offline)